Economic evaluation of clopidogrel plus aspirin for secondary prevention of cardiovascular events in Canada for patients with established cardiovascular disease: Results from the CHARISMA trial

Background

The Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance (CHARISMA) trial found a statistically significant reduction in cardiovascular events when clopidogrel was added to aspirin in a prespecified subgroup of patients with established cardiovascular disease. However, the economic implications of such a strategy for the Canadian health care system are unknown.

Methods

For each patient in the CHARISMA trial with established cardiovascular disease, costs were estimated by multiplying resource utilization by unit costs derived from populations of Canadian patients in 2008 dollars. Changes in life expectancy due to nonfatal events were estimated with parametric regression models based on the Saskatchewan Health database.

Results

For patients with established cardiovascular disease, a strategy of clopidogrel plus aspirin for median duration of 28 months was associated with a 12.5% relative reduction in cardiovascular death, myocardial infarction, or stroke compared with aspirin alone (6.9% vs 7.9%, P =.048). Mean cost per patient was CAD$1,488 higher for clopidogrel plus aspirin, and life expectancy increased by 0.057 years. The resulting incremental cost-effectiveness ratio for adding clopidogrel was CAD$25,969 per life-year gained or CAD$21,549 per quality-adjusted life-year. These results were sensitive to the cost of clopidogrel but relatively insensitive to plausible variations in discount rate, costs other than clopidogrel, and the prognostic impact of nonfatal events.

Conclusion

Among the subgroup of patients with established cardiovascular disease in the CHARISMA trial, adding clopidogrel to aspirin increases life expectancy at a cost generally considered acceptable in Canada.     

BI-RADS 3类病变(即可能良性病变分类)在美国放射学会影像网(ACRIN)的数字化乳腺摄影筛查试验(DMIST)中的诊断价值

目的本研究旨在明确以下3方面问题:其一,当行乳腺X线摄影筛查或行补充检查后,在美国放射学会影像网(ACRIN)的数字化乳腺摄影筛查试验(DMIST)中BI-RADS3类病变的诊断率为多少;其二,在建议进行随访观察     

Acute, low-dose methamphetamine administration improves attention/information processing speed and working memory in methamphetamine-dependent individuals displaying poorer cognitive performance at baseline

Abstinent methamphetamine (Meth) dependent individuals demonstrate poorer performance on tests sensitive to attention/information processing speed, learning and memory, and working memory when compared to non-Meth dependent individuals. The poorer performance on these tests may contribute to the morbidity associated with Meth-dependence. In light of this, we sought to determine the effects of acute, low-dose Meth administration on attention, working memory, and verbal learning and memory in 19 non-treatment seeking, Meth-dependent individuals. Participants were predominantly male (89%), Caucasian (63%), and cigarette smokers (63%). Following a four day, drug-free washout period, participants were given a single-blind intravenous infusion of saline, followed the next day by 30 mg of Meth. A battery of neurocognitive tasks was administered before and after each infusion, and performance on measures of accuracy and reaction time were compared between conditions. While acute Meth exposure did not affect test performance for the entire sample, participants who demonstrated relatively poor performance on these tests at baseline, identified using a median split on each test, showed significant improvement on measures of attention/information processing speed and working memory when administered Meth. Improved performance was seen on the following measures of working memory: choice reaction time task (p ≤ 0.04), a 1-back task (p ≤ 0.01), and a 2-back task (p ≤ 0.04). In addition, those participants demonstrating high neurocognitive performance at baseline experienced similar or decreased performance following Meth exposure. These findings suggest that acute administration of Meth may temporarily improve Meth-associated neurocognitive performance in those individuals experiencing lower cognitive performance at baseline. As a result, stimulants may serve as a successful treatment for improving cognitive functioning in those Meth-dependent individuals experiencing neurocognitive impairment.     

Dental CT metal artefact reduction based on sequential substitution

Objective: Metal artefacts can seriously degrade the visual quality and interpretability of dental CT images. Existing image processing algorithms for metal artefact reduction (MAR) are either too computationally expensive to be used in clinical scanners or effective only in correcting mild artefacts. The aim of the present study was to investigate whether it is possible to improve the efficacy of the computationally efficient projection-correction approach to MAR by exploiting the spatial dependency or autocorrelation between adjacent CT slices.Methods: A new projection-correction algorithm [MAR by sequential substitution (MARSS)] was developed based on the idea that the corrupted portions of the projection data can be substituted with the corresponding portions from an unaffected adjacent slice. The performance of MARSS was evaluated relative to the projection-correction method of Watzke and Kalendar using a two-alternative forced choice (2AFC) visual trial involving 20 observers and 20 clinical CT data sets.¹⁶Results: The Cochran Q test revealed no significant difference in the responses across all observers. The data were then pooled and analysed using a one-tailed exact binomial test. This revealed that the proportion of responses in favour of MARSS was significant (P < 2.2 × 10⁻¹⁶). A second Cochran Q test revealed no significant difference in the responses across all images.Conclusions: It is possible to improve the efficacy of projection correction by exploiting spatial autocorrelation. The 2AFC results suggest that the proposed MARSS algorithm outperforms competing computationally efficient algorithms in terms of reducing metal artefacts whilst at the same time preserving/revealing anatomic detail.     

CAGS and ACS Evidence Based Reviews In Surgery. 37: Is there a role for prophylactic antibiotics in the prevention of urinary tract infections following Foley catheter removal in patients having abdominal surgery?

Question: Does the use of antibiotic prophylaxis at urinary catheter removal reduce the rate of urinary tract infection? Design: Randomized controlled trial. Setting: Single centre in Basel, Switzerland. Patients: A total of 239 patients between January 2005 and September 2007 were randomly assigned into 2 groups by an online randomization generator. Intervention: Patients undergoing elective abdominal surgery with planned perioperative urethral catheterization were assigned at admission to receive either 960 mg of trimethoprim-sulfamethoxazole orally the night before and twice on the day of catheter removal or no antibiotic prophylaxis. Urinary cultures were obtained before and 3 days after catheter removal. Main outcome measures: Occurrence of symptomatic urinary tract infection (based on the Centers for Disease Control and Prevention definitions) after catheter removal. Results: Patients who received antibiotic pro-phylaxis experienced significantly fewer urinary tract infections than those who did not (5 of 103 [4.9%] v. 22 of 102 [21.6%], p < 0.001; number needed to treat 6). Patients who received antibiotic prophylaxis also had less significant bacteriuria 3 days after catheter removal than those who did not (17 of 103 [16.5%] v. 42 of 102 [41.2%], p < 0.001). Conclusion: Antibiotic prophylaxis with trimethoprim-sulfamethoxazole at the time of urinary catheter removal significantly reduces the rate of symptomatic urinary tract infections and bacteriuria in patients who undergo abdominal surgery and perioperatively receive transurethral urinary catheters.